NEG Coatings and their Potential to Make a Major Impact on Future Advanced Particle Accelerators

邀请申请者参加2019年10月开始的为期3.5年的博士课程，学习对未来粒子加速器至关重要的技术开发，这是一个令人兴奋的机会。非蒸散型吸气剂(NEG)涂层最初是由欧洲核子研究中心发明的，目前已被许多加速器使用，原因主要有三点：(1)它减少了热、电子和离子诱导的气体解吸，起到了阻挡真空室材料与内真空之间的作用；(2)全涂层真空室具有很大的分布抽气速度，这对真空电导有限的狭窄容器至关重要；(3)NEG涂层具有低二次电子(SEY)产额，有助于抑制高强度加速器中的电子多碰撞和电子云。负涂层是下一代加速器真空系统最有前途、最经济的解决方案。ASTEC，这一领域的世界领先者，正致力于NEG的优化，以优化NEG涂层的所有三个好处。这项技术的进一步发展需要在跨学科领域开展工作：加速器、材料和真空科学。在进一步的NEG涂层优化中有两个主要挑战：(1)NEG涂层腔中的束阻抗，它与束流参数和NEG涂层电阻有关，这是短束流机的问题；(2)NEG涂层在直径小于10 mm的窄管上的涂层，这是像未来的UK-XFEL这样的小口径机器的问题。

Applications are invited for an exciting opportunity to study for a 3.5-year PhD commencing Oct 2019 on the development of technologies that are critical for future particle accelerators. Non-evaporable getter (NEG) coating, originally invented at CERN, is already used in many accelerators due to three main properties: (1) it reduces thermal and photon, electron and ion induced gas desorption acting as a barrier between a vacuum chamber material and an inner vacuum; (2) a fully coated vacuum chamber has large distributed pumping speed, the benefit of this is essential for the narrow vessels with a limited vacuum conductance; (3) the NEG coating has low secondary electron (SEY) yield that helps to supress electron multipacting and electron cloud in high intensity accelerators. NEG coating is the most promising and most economic solution for a vacuum system of the next generation accelerators. ASTeC, world leader in this area, is working on optimisation of NEG on optimising all three NEG coating benefits. Further development of this technology require working on interdisciplinary field: accelerator, material and vacuum science. There are two main challenges in further NEG coating optimisation: (1) the beam impedance in the NEG coated chamber, which related to beam parameters and NEG coating resistance, this is a problem for short-bunch machines; (2) coating of NEG on narrow tubes with a diameter less than 10 mm, this is a problem for small aperture machines like a future UK-XFEL.